Introduction to the Reproductive System Objective Specify the principal components of the human reproductive system amp summarize their functions Reproductive System The reproductive system ID: 776553
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Slide1
Chapter 28
The Reproductive System
Slide2Introduction to the Reproductive System
Objective:
-Specify the principal components of the human reproductive system & summarize their functions.
Slide3Reproductive System
The
reproductive system
is the only system that is not essential to the life of the individual
It ensures the continued existence of human beings:
-by producing, storing, nourishing, and transporting functional male and female reproductive cells, or
gametes
Slide4Components of the Reproductive System
Gonads:
the reproductive organs that produce gametes and hormones
Ducts that receive and transport gametes
Accessory glands & organs that secrete fluids into the ducts
Perineal
structures, known an
external genitalia
Slide5Male Components
Testes:
male gonads
Secrete sex hormones such as testosterone
Produce male gametes, called
spermatozoa
(1/2 billion each day)
During
emission
, mature sperm mix with secretions to form a mixture called
semen
Semen is expelled during
ejaculation
Slide6Female Components
Ovaries: female gonads
Release one immature gamete (
oocyte
), per month
Oocyte travels along
uterine tubes
, which end in a muscular organ known as the
uterus
Slide7Fertilization
Oocyte matures into an ovum
Ejaculation
introduces semen into the vagina during
sexual intercourse
If fertilization occurs, the uterus will enclose and support a developing
embryo
as it grows into a
fetus
Slide8The Reproductive System of the Male
Objectives:
Describe the components of the male reproductive system
Outline the processes of meiosis & spermatogenesis in the testes
Explain the roles played by the male reproductive tract in the handling of spermatozoa
Slide9The Testes
Shape of a flattened egg
Hangs within the
scrotum
: a fleshy pouch suspended posterior to the base of the penis
Slide10The Testes
Ureter
Rectum
Seminal
vesicle
Prostate
gland
Ejaculatory duct
Bulbourethral gland
Anus
Urinary
bladder
Pubic
symphysis
Spongy urethra
Penis
Ductus deferens
Epididymis
Testis
Scrotum
External urethral
orifice
Slide11Descent of the testes
During development of fetus, testes develop inside the body cavity, adjacent to kidneys
Position of testes changes as body enlarges
Testes gradually move inferiorly and
anteriorly
toward anterior abdominal wall
Descent of the testes
is the process of the testes moving through the abdominal musculature
Slide12Descent of the Testes
Epididymis
(b)
Diaphragmatic
ligament
Developing
kidneys
Gubernaculum
testis
Mesonephric
duct
Kidney
Testis
Epididymis
Testis
Urinary
bladder
Ureter
Vas
deferens
Epididymis
Testis
Gubernaculum
testis
Superficial
inguinal ring
Testicular
artery and
vein
Testicular
artery and
vein
Gonads
Scrotal cavity
(opened) lined by
tunica vaginalis
2 months
3 months
4 months
7 months
Diaphragmatic
ligament
Urinary
bladder
Scrotum
(opened)
Ureter
Birth
Spermatic
cord
Slide13Descent of the Testes
Cryptorchidism
is a condition where one or both of the testes have not descended into the scrotum b the time of birth
They are lodged in the abdominal cavity or within the inguinal canal
The person may become infertile or
sterile
Slide14The Spermatic Cords
These are layers of fascia and muscle enclosing the
ductus
deferens and the blood vessels, nerves, and lymphatic vessels that supply the testes
Slide15The Scrotum and the Position of the Testes
Testicular artery
Testicular vein
Inguinal
ligament
Superficial
inguinal ring
Scrotal septum
Cremaster muscle
Dartos muscle
Superficial scrotal
fascia
Raphe
Scrotal skin (cut)
Testis (covered by
Visceral layer of
tunica vaginalis)
Epididymis
Pampiniform plexus
Ductus deferens
Deferential artery
Genitofemoral nerve
Testicular artery
Spermatic cord
Inguinal
canal
Urinary
bladder
Penis
Parietal layer of tunica
vaginalis (inner lining
of cremaster muscle,
facing scrotal cavity)
Scrotal cavity
Slide16The Scrotum
The scrotum is divided into two
scrotal cavities
, marked by a raised thickening in the scrotal surface known as the
raphe
It consists of a thin layer of skin and underlying superficial fascia
Layers of the smooth & skeletal muscle results in the wrinkling of the scrotal surface
Moves the scrotum to or from the body to provide the desired temperature for sperm production (two degrees Fahrenheit)
Slide17Spermatogenesis
Three processes:
Mitosis: 2 daughter cells produced: one is turned into a
spermatocyte
(cell that begins meiosis)
Meiosis: produces
spermatids
(undifferentiated male gametes)
Spermiogenesis
: spermatids differentiate into mature spermatozoa
Slide18Spermatogenesis
Tetrad
Synapsis and
tetrad formation
MITOSIS of
spermatogonium (diploid)
MEIOSIS I
MEIOSIS II
Secondary spermatocytes
Spermatids (haploid)
SPERMIOGENESIS(physical maturation)
Spermatozoa (haploid)
Primary spermatocyte
Primary spermatocyte (diploid)
DNA replication
SPERMATOGENESIS
Slide19Sustentacular Cells
Play a key role in spermatogenesis
Maintenance of the blood-testes barrier
Support of Mitosis and Meiosis
Support of Spermiogenesis
Secretion of Inhibin
Secretion of Androgen-Binding Protein
Secretion of
Mullerion
-Inhibiting Factor
Slide20Anatomy of Spermatozoon
Three Distinct Regions:
Head
: flattened ellipse containing a nucleus with densely packed chromosomes
Middle piece
: contains mitochondria to provide energy to move tail
Tail
: the flagellum that beats in a corkscrew motion to propel sperm
Slide21Anatomy of Spermatazoon
(a)
Mitochondria
Spermatid
(week 1)
Spermatozoon
(week 5)
Golgi
apparatus
Acrosomal
vesicle
Nucleus
Acrosomal
cap
Nucleus
Acrosomal
cap
Tail (55
m)
Middle piece
(5
m)
Neck (1
m)
Head (5
m)
Mitochondrial
spiral
Centrioles
Nucleus
Acrosomal cap
Shed
cytoplasm
Fibrous sheath
of flagellum
Slide22The Male Reproductive Tract
The
Epidymis
: start of the male reproductive tract
Three Functions:
Monitors and adjusts composition of fluid produced by seminiferous tubes
Acts as a recycling center for damaged sperm
Stores and protects spermatozoa and facilitates their functional
maturization
Slide23Male Reproductive Tract
Ductus Deferens
: passageway that carries spermatozoa from epidymis to the
ejaculatory duct
, which empties into the urethra
Urethra: passageway for urinary and reproductive system to the outside environment
Slide24Male Reproductive Tract
LM X 1304
(a)
(b)
Body of
epididymis
Ductus
deferens
Tail of
epididymis
Scrotal
cavity
Tunica
albuginea
Testis
Seminiferous
tubule
Rete testis
Head of
epididymis
Spermatic cord
Efferent
ductules
Epithelium
of
epididymis
Stereocilia
Flagella of
spermatozoa
in lumen of
epididymis
Slide25Accessory Glands
The seminal vesicles, prostate gland, and
bulbourethral
glands give semen a mixture of secretions
Four Functions:
Activate spermatozoa
Provide nutrients spermatozoa need for motility
Propel spermatozoa and fluid along reproductive trace
Produce buffers that counteract acidity of the urethral and vaginal environments
Slide26Accessory Glands
(a)
Ureter
Ductus deferens
Seminal vesicle
Ampulla of
ductus deferens
Prostate gland
Urethra
Bulbourethral
gland
Ejaculatory duct
Duct of
seminal vesicle
Urinary
bladder
Urogenital
diaphragm
Prostatitis
is the inflammation of the prostate caused by a bacterial infection.
Symptoms are pain in lower back,
p
erineum, and painful urination
Slide27Semen
Typical ejaculation releases 2-5ml of semen
Volume of fluid produced by an ejaculation, called an
ejaculate
, contains:
Spermatozoa: 20-100 million per ml of semen
Seminal Fluid
Enzymes
Slide28External Genitalia
Consists of the scrotum and the penis
The penis is a tubular organ that conducts urine to exterior and semen into a female’s vagina during sexual intercourse
Three parts:
Root
: fixed portion that attaches penis to body wall
Body
(shaft): tubular, movable portion
Glans
: expanded distal end that surrounds external/ urethral orifice
Slide29Penis
Most of body consists of three cylindrical columns of
erectile tissue
When smooth muscle relaxes, blood flow increases and the vascular channels engorge with blood. This causes an
erection
.
Slide30Testosterone
Five functions:
Stimulates spermatogenesis and promotes functional maturation of spermatozoa
Affects CNS function, including libido(sexual drive) and related behaviors
Stimulate metabolism throughout the body
Establishing and maintaining male secondary sex characteristics (facial hair, increased muscle mass and body size)
Maintaining accessory glands and organs of the reproductive tract
Slide31The Reproductive System of the Female
Objectives:
Describe the components of the female reproductive system
Outline the processes of meiosis and oogenesis in the ovaries
Identify the phases and events of the ovarian and uterine cycles
Describe the structure, histology, and functions of the vagina
Summarize the anatomical, physiological, and hormonal aspects of the female reproductive cycle
Slide32Woman’s Reproductive System
Produces sex hormones and functional gametes
Protects and supports a developing embryo and nourishes a newborn infant
Principle organs are the ovaries, uterine tubes, uterus, and vagina
Slide33Woman’s Reproductive System
Uterine tube
Broad ligament
Ovary
Vesicouterine pouch
Urinary bladder
Pubic symphysis
Urethra
Greater vestibular gland
Clitoris
Labium minus
Labium majus
Anus
Vagina
Cervix
Fornix
Sigmoid colon
Rectouterine
pouch
Endometrium
Perimetrium
Uterus
Myometrium
Paraurethral
glands
Rectum
Slide34The Ovaries
Three main functions:
Production of immature gametes, or
oocytes
Secretion of female sex hormones (estrogen)
Secretion of
inhibin
, involved in the feedback control of pituitary FSH production)
A typical ovary is 5cm long, 2.5cm wide, and 8mm thick
Slide35The Ovaries
(b)
(a)
Uterine
tube
Mesovarium
Medulla
Corpus
luteum
Cortex
Tunica
albuginea
Mature
follicle
Egg nest
Ovarian
hilum
Broad
ligament
Uterus
Ovarian
ligament
Uterine tube
Fimbriae
Ovarian artery
and vein
Suspensory
ligament
Infundibulum
Ureter
Uterosacral ligament
Vaginal wall
Cervix
Cervical os
Vaginal rugae
Ovary
Broad
ligament
Broad
ligament
Suspensory
ligament
Mesovarium
Retractor
Slide36Oogenesis
Oogensis
, or ovum production, begins before a woman’s birth, accelerates at puberty, and ends at
menopause
Occurs on a monthly basis as part of the
ovarian cycle
Development of oogonia, or female stem cells, stop undergoing meiosis before birth
Does not turn into an ovum until puberty
Slide37Oogenesis
Tetrad
OOGENESIS
Primary
oocyte
(may not
occur)
Secondpolarbody
Secondary oocyte (haploid)
If fertilization occurs after ovulation, MEIOSIS II is completed
Secondary oocyteovulated in metaphaseof MEIOSIS II
Ovum(haploid)
Primary oocyte (diploid)
MEIOSIS I completed after puberty
Synapsis and tetrad formation
DNA replication (before birth)
MITOSIS ofoogonium(before birth)
Maturation of gamete
MEIOSIS II begun in the tertiary follicle and completed only if fertilization occurs
First polar
body
Slide38The Ovarian Cycle
The
Ovarian Cycle
is the monthly chain of events that leads to ovulation
It is divided into two phases:
Follicular phase
Luteal phase
Ovarian follicles are specialized structures in the cortex of ovaries where both oocyte growth and meiosis 1 occur
Slide39The Ovarian Cycle
It involves six steps:
Formation of primary follicles
Formation of secondary follicles
Formation of tertiary follicles
Ovulation
: the tertiary follicle releases the secondary oocyte and is transferred to the uterine tube
Formation & degeneration of the
Corpus
Luteum
(endocrine structure formed to prepare uterus for pregnancy)
Unless fertilization occurs, the Corpus
Luteum
begins to degenerate
Slide40The Ovarian Cycle
STEP
STEP
STEP
Tertiary
follicle
Primary
oocyte
Follicle
cells
Ovary
Thecal
cells
Zona
pellucida
Primordial follicles
in egg nest
Granulosa
cells
Primary
oocytes
Primary oocyte
Antrum
containing
follicular
fluid
Granulosa
cells
Primary
follicles
Secondary
follicle
Granulosa
cells
Nucleus of
primary
oocyte
Zona
pellucida
Thecal
cells
1
2
3
STEP
STEP
STEP
Corpus albicans
Released
secondary oocyte
Secondary
oocyte within
corona radiata
Follicular
fluid
Ruptured
follicle wall
Outer
surface
of ovary
Ruptured tertiary follicle
Corona radiata
Ovulation
Corpus luteum
4
5
6
Slide41The Uterine Tubes
The
uterine tubes
are hollow muscular tubes
Peristaltic contractions move ovum towards uterus
It takes 3-4 days for ovum to travel to uterus
It provides nutrients to the sperm and developing pre-embryo
Slide42The Uterus
The
uterus
provides mechanical protection, nutritional support, and waste removal for developing embryo
Contractions in muscular wall help eject the fetus at birth
Slide43The Uterus
(a)
Uterus
Isthmus
Ampulla
Infundibulum
Fimbriae
Posterior view
Slide44The Uterine Cycle
The
uterine cycle
is a repeating series of changes in the structure of the inner layer of the uterus (28 days in length)
Slide45The Uterine Cycle
Three phases:
Menses
Menses: interval marked by the degeneration of the inner layer of the uterus
Menstruation: process of losing 35-50ml of blood
The Proliferative Phase
Epithelial cells multiply and restore the uterus epithelium
The
Secretory
Phase
Glands enlarge, accelerating rate of secretion
Slide46Menarch and Menopause
Menarch
is the first cycle at puberty, normally at age 12
Menopause
is the termination of the uterine cycle, normally between the ages of 45-55
Slide47The Vagina
The
vagina
is an elastic, muscular tube extending between the cervix and the
vestibule
, bounded by external genitalia
The
vaginal canal
is the proximal end where the cervix project into
Slide48The Vagina
Three Functions:
Passageway for the elimination of menstrual fluids
Receive the penis during sexual intercourse, and holds sperm prior to passage into the uterus
Forms inferior portion of
birth canal
Slide49Anatomy & Histology of the Vagina
Lined by nonkeratinized stratified squamos epithelium (when relaxed, folds form rugae)
Lining is moistened by secretions
Contains a population of resident bacteria
Metabolic activity creates an acidic environment
Vaginitis
is an inflammation of the vaginal canal caused by fungi, bacteria, or parasites
Causes discomfort and reduced fertility
Slide50The External Genitalia
The
vulva
is the area containing the female external genitalia
Vagina opens into the vestibule
The
clitoris
is a small rounded projection that engorges with blood during sexual intercourse
Slide51The External Genitalia
Anus
Labia
majora
Labia
minora
Glans of
clitoris
Mons pubis
Prepuce
of clitoris
Urethral
opening
Vestibule
Vaginal
entrance
Hymen (torn)
Slide52The Mammary Glands
Mammary glands
, in a woman’s breast, produce milk to feed their newborn infant
Each breast has a
nipple
, where the underlying mammary gland opens to the body surface
Slide53Mammary Glands
(a)
Pectoralis
major muscle
Pectoral fat pad
Suspensory
ligaments
Lactiferous
duct
Areola
Nipple
Lactiferous
sinus
Lobes of the
mammary gland
Slide54Hormones
Circulating hormones control the
female reproductive cycle
, coordinating the ovarian and uterine cycles
Slide55Estrogen
Estrogen has five main functions:
Stimulating bone and muscle growth
Maintaining female sex characteristics
Affecting CNS activity
Maintaining functional accessory reproductive glands and organs
Stimulating the repair and growth of the inner layer of the uterus
Slide56The Physiology of Sexual Intercourse
Objective:
Discuss the physiology of sexual intercourse as it affects the reproductive systems of males and females
Slide57Male Sexual Function
During sexual
arousal
, erotic thoughts, stimulation of sensory nerves in genital region, lead to an erection of the penis
Ejaculation
is the ejection of semen from the penis as the result of muscular contraction along the sides of the penis
Associated with intensely pleasurable sensation known as orgasm
Impotence
is the inability to achieve or maintain an erection
Slide58Female Sexual Function
During sexual arousal, engorgement of erectile tissue of clitoris
Orgasm is found by stimulation of touch sensations
Contractions of uterine and vaginal wall gives rise to pleasurable sensations
Slide59Sexual Transmitted Disease
STD
’s are transferred primarily during sexual intercourse
Chlamydia
can cause
pelvic inflammatory disease
as well as
infertility
Slide60Jobs in the Reproductive Field
Gynecologist
-study
and treat problems with the female genital, rectal and urinary
organs
Fertilization Researcher
-
studies the effects of in-vitro fertilization, stem cell biology, animal assisted reproductive methods and the effects of different toxins on a
fetus
Urologist
-A physician who specializes
in
diseases of the urinary organs in females and the urinary and sex organs in males.
Slide61Aging and the Reproductive System
Objective:
Describe the changes in the reproductive system that occur with aging
Slide62Menopause
Menopause
is the time the ovulation and menstruation cease
Premature menopause is a depletion of follicles before age 40
Is accompanied by a decline of estrogen which leads to reductions of uterus and breasts; even linked to osteoporosis
Slide63The Male Climacteric
Male Climacteric is the period of declining reproductive function
Circulating testosterone decreases between ages 50-60
Sperm production continues, but reduction in sexual activity
Slide64Integration with Other Systems
For proper function, reproductive, digestive, endocrine, nervous, cardiovascular, and urinary systems must all function normally
Slide65Clinical Patterns
Reproductive Disorders
Tumors, such as testicular, prostate, ovarian, or uterine cancers
Inflammation and infection, such as
prostatitis
, PED, toxic shock syndrome, and STD’s
Uterine disorders such as endometriosis
Trauma, such as testicular torsion and inguinal hernias
Congenital disorders, such as
crytorchidism
Slide66Finished!!!